Fluid simulation fall out of glass?
This may be beause the physics simulation are too rough in comparison to your glass movement speed. You can adjust that by going to Properties Panel -> Scene (3rd icon in the rop row) -> scroll down to "Rigid Body World" -> Increase the values of "Steps per Second" and maybe also "Solver Iterations"

It's also always a good idea to enable "Split Impulse" on that panel.

Comment if this has solved your issue